Snap-action condition responsive switch



y 2 1965 SHIGEO MAMIYA ETAL v 3,185,796

SNAP-ACTION CONDITION RESPONSIVE SWITCH Filed D sc. 14, 1961 2 Sheets-Sheet l INVENTORS SHIGEO MAMIYA TAKESHI ODASHIMA BY Ute M1 Attorney y 25, 1955 SHIGEO MAMIYA ETAL 3,185,796

SNAP-ACTION CONDITION RESPQNSIVE SWITCH Filed Dec. 14, 1961 2 Sheets-Sheet 2 Fig. 3

lNlEfl/TORS SHIGEO MAMIYA TAKESHI ODASHIMA BY 0Z1,

Attorney ,689/ 61 9 Claims. (Cl. 200-140) This invention relates to an automatic switch.

An object of the present invention is to provide an automatic pressure switch which is small and compact and which can be adjusted for a wide range of operating temperatures and pressures and canbe used for many purposes.

Another object of the present invention is to provide a switch which will be automatically operated when the effective temperature or pressure becomes higher or lower than a desired predetermined value above the corresponding value of the ambient atmosphere.

A further object of the present invention is to provide an automatic switch which is adjustable to a high degree of accuracy over a wide range.

With these and other objects hereinafter set forth, an embodiment of the present invention is fully described in the ensuing specification.

In the accompanying drawings,

FIGURE 1 is a vertically sectioned side view;

FIGURE 2 is a right side view;

FIGURE 3 is a left side view with a part of the casing broken away to disclose internal details of construction;

FIGURE 4 is a plan view;

FIGURE 5 is a plan view of an operating plate part.

1 is a sensitive tube part enclosing a temperature sensitive fluid and connected at one end with a capsule comprising lower diaphragm 2 and an upper diaphragm 3 having a bearing 4 in contact with a point bearing 6a of the horizontal side part of a first operating plate or lever 7 L- shaped in side elevation and rotatably supported on fulcrum bearings 6 formed on a frame 5. See FIG. 5. A slot 8 is made in the vertical side part of the operating plate 7. A machine screw 9 is inserted freely in said slot 8 and is screwed into the threaded aperture of part 10' connected with one end of a coil spring 10. This spring is connected at its other end with an adjusting plate 13 operatively connected with a spiral cam plate 12 fixed to a rotary shaft 11 journaled at the top of the instrument for rotation about a vertical axis as viewed upon FIG. 1. 14 is a second operating forked plate or lever and supported rotatably on fulcrum bearings 15 formed on the frame and connected operatively with said first operating plate 7 through a leaf or toggle spring of an inverted U-shape as clearly shown upon FIG. 1. From FIG. 5 it is seen that bearings 6, 6 and 15, 15 define, respectively, first and second pivot axes which are parallel and contiguous.

The second operating plate 14 is in contact at one end with the lower end of a vertical rod 19 slidably fitting a vertical hole 18 in a terminal block 17 fixed to one side of the instrument casing. Said vertical rod 19 is in contact at its upper end with a movable spring contact arm 20, and positioned to make and break contact with a fixed contact 21. 22 is a bolt for adjusting the vertical range of movement of the second operating plate 14 and is to adjust the temperature difference or the pressure difference for opening and closing the contacts. 23 is a resilient plate secured by a screw 24 to the vertical side part of the first operating plate 7 and having a slot 25 and a small hole 26 pressing the head of bolt 9 on which is the aforesaid coil spring.

In operation when the gas pressure within the sensitive tube 1 rises with the rise of the atmospheric temperature,

United States Patent I 3 ,185,796 Patented May 25, 1965 the upper diaphragm 3 will be deflected upwardly and therefore the first operating plate 7 will be pivoted counterclockwise as viewed upon FIG. 1, about fulcrum bearings 6, by bearing 4, against the tension of the spring 10 (in FIGURE 1). Therefore, the second operating plate 14 operatively connected with said first operating plate 7 through the inverted U-shaped leaf spring 16 will rotate with a snap action, clockwise about its fulcrum bearings 15. With the rotation of said second operating plate, the vertical rod 19 in contact with one end of said plate and inserted in the vertical hole 18 in the terminal block 17 will fall and the movable contact 20 which has been in contact with the upper end of the vertical rod 19 and thereby held out of engagement with fixed contact 21, will come into contact with the fixed contact 21. When the gas pressure within the sensitive tube 1 decreases an operation reverse to the above description will take place. That is to say, when the tension of the coil spring 10 becomes stronger than the gas pressure on the upper diaphragm 3, the first operating plate 7 will rotate clockwise in FIGURE 1 and then the second operating plate 14 will rotate quickly anticlockwise. Therefore, the vertical rod 19 in contact with one end of the second operating plate 14 will rise and its upper end will elevate the movable contact plate 20 out of contact with the fixed contact 21 so as to open the electric circuit.

The temperature range of the switch of the present invention is adjusted by first varying the tension of the coil spring 10. For this purpose, as the spring is connected at one end to adjusting plate 13 oscillated by the cam plate 12, the range can be varied by the rotation of the rotary shaft 11 to which is fixed the cam plate 12.

According to the present invention, the tension of the coil spring can be varied finely by rotating the screw 9 on which said coil spring is hung at the other end. When the movement of the switch is to be varied outside such fixed range, the ratio or leverage of the distance 1 between the fulcrum 6 of the first operating plate and the bolt 9 to the distance between the fulcrums 6 and 6a is varied by moving the bolt 9 within the slot 8 made in the 1 vertical side part of the first operating plate 7 so that the range of adjustment may be further increased and wider adjustment may be possible.

Further, as the bolt 9 is normally pressed on the head part by the resilient plate 23 toward the first operating plate, it will not be accidentally displaced from adjusted position. A so-called kicking mechanism is adopted for opening and closing the contact part so that the burning of the contact may be prevented. The terminal block 17 is formed of an insulator. The vertical rod 19 is also formed of an electrically insulating material. Therefore, no electric current is likely to leak out to any other part. When the adjusting bolt 22 screwed into the lower end of the terminal block 17 is raised, the lower limit of temperature at which the contacts will open, will be raised independently of the temperature (pressure) for closing the contact, that is to say, the temperature range between for opening and closing the contact will be decreased.

Although the invention has been described hereinbefore with reference to the specific embodiment, it is to be understood that this embodiment may be modified in many ways within the scope of the invention as defined in the appended claims. 7

In the claims, the term normal or normally as used in connection with the positions of lever or plates 6 and 14, refers to their positions as shown upon FIG. 1.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. in a condition responsive switch, first and second levers, first means mounting said levers in normally coplanar relation for independent pivotal movement about sneer/9e respective adjacent first and second parallel axes in the common plane thereof, said levers including respective first and second confronting adjacent abutments in said plane and offset from said axes, a toggle spring interposed between and engaging said abutments to exert a force normally in said plane and urging said abutments apart, second means engaging said first lever in offset relation with said first axis and eifective to pivot said first lever in one direction, by and in response to a change in pressure, spring means connected with said first lever and urging the same into pivotal movement in the opposite direction, and contact closing means responsive to pivoting of said second lever about said second axis.

2. The switch of claim 1, said first lever having an arm extending normally to and out of said plane, an adjusting part mounted for movement in a direction parallel wit said plane in position offset therefrom, said spring means comprising a coil spring having its ends connected respectively, with the distal end of said arm and said part.

3. The switch of claim 2, said direction being normal to said first and second axes, and a spiral cam having its cam edge engaging said part and rotatable to adjust the same.

4. In a pressure responsive switch, a frame, first and second levers, first means mounting said levers in said frame for pivoting about independent first and second parallel adjacent axes defining a plane, said levers having first and second opposed abutments normally in said plane and offset from said axes, a spring interposed between and engaging said abutments and normally exerting a force in said plane urging said abutments apart, pivotal movement of said first lever in one direction or the other about its said first axis, effecting through said spring a moment on said second lever pivoting the same in the opposite direction, an expansible bellows having a portion engaging said first lever at a point between said first axis and said first abutment, to pivot the same in one direction by and in response to a change in pressure, spring means connected with said first lever and urging the same into pivoting in the opposite direction, and circuit closure switch means operated by and in response to pivotal movement of said second lever about said second axis.

5. In a pressure responsive switch, a frame, first and second levers, first means mounting said levers in said frame for pivoting about independent first and second parallel adjacent axes defining a plane, said levers having respective first and second opposed abutments normally in said plane and offset from said axes, a spring interposed between and engaging said abutments and normally exerting a force in said plane urging said abutments apart, pivotal movement of said first lever in one direction or the other about its first axis, effecting through said spring a moment on said second lever pivoting the same in the opposite direction, a device engaging said first lever to pivot the same in one direction by and in response to a change in pressure, spring means connected with said first lever and urging the same into pivoting in the opposite direction, a first contact fixed with said frame, a spring arm having a second contact at one end and normally stressed thereby into engagement with said first contact, a rod mounted in said frame for axial translation in a direction normal to said plane, said rod at one end engaging said second lever and at its other end said spring to separate said contacts by and in response to one direction of pivoting of said second lever about said second axis.

6. In a pressure-responsive switch, a frame, first and second levers, first means mounting said levers to said frame for pivoting about respective fixed first and second parallel contiguous axes defining a plane, said levers having respective first and second confronting bearings spaced in said plane and offset from said axes, a toggle spring carried by and interposed between said bearings and normally exerting a force in said plane urging said bearings apart, contact means carried by said frame and engaged by said second lever for closure in response to pivoting thereof, said first lever having an integral arm extending normal to said plane, the distal end of said arm being slotted in a direction normal to said plane, a screw having a head journaled in said slot with its axis parallel with and offset from said plane and adjustable along said slot to vary the spacing therefrom, a coil spring having its axis aligned with said screw, an element carried by said spring at one end thereof and threadedly engaging said screw, and means fixed with the other end of said spring and adjustable along the axis thereof.

7. The switch of claim 6, a lock element having an aperture smaller than the fitting over the head of said screw to lock the same to said arm in adjusted position along said slot, means mounting said lock element on said arm for adjustment with said screw, and means clamping said lock element to said arm for fixation of said screw in adjusted position in and along said slot.

8. The switch of claim 6, said last-named means including a part translatable along the axis of said coil spring, a spiral cam journaled for rotation in said frame about an axis normal to said plane and having its cam surface in contact with said part, rotation of said cam effecting translation of said part to vary the force movement with which said coil spring urges said first lever about said first axis in one direction of pivoting, and pressure responsive bellows means engaged with said first lever and operable to urge the same in the opposite direction of pivoting about said first axis.

9. A switch comprising a frame, first and second levers, means mounting said levers in said frame for pivotal movement about respective first and second parallel contiguous axes, said axes determining a reference plane, said levers having respective first and second abutments normally spaced in said plane remote from and on one side of said axes, a toggle spring acting on and between said abutments to exert a force therebetween, normally in said plane, means engaging said first lever and operable to pivot the same in one direction in response to a change in condition, spring means acting between said frame and first lever and urging the latter into pivoting in the opposite direction, contact means engaging said second lever and operated by pivoting thereof in response to pivoting of said first lever, and means adjustable to engage and limit the range of pivoting of said second lever.

References Cited by the Examiner UNITED STATES PATENTS 1,507,591 9/ 24 Prankenberg 200-140 1,791,896 2/31 Heming 200-14O 1,827,102 10/31 Pem 200-140 2,491,338 12/49 Smith 200140 2,702,336 2/55 Wagner et al 200 X 2,845,504 7/ 58 Iglehart 20067 2,853,582 9/58 Rauh 200 3,065,323 11/62 Grimshaw 200168 X BERNARD A. GILHEANY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner. 

1. IN A CONDITION RESPONSIVE SWITCH, FIRST AND SECOND LEVERS, FIRST MEANS MOUNTING SAID LEVERS IN NORMALLY COPLANAR RELATION FOR INDEPENDENT PIVOTAL MOVEMENT ABOUT RESPECTIVE ADJACENT FIRST AND SECOND PARALLEL AXES IN THE COMMON PLANE THEREOF, SAID LEVERS INCLUDING RESPECTIVE FIRST AND SECOND CONFRONTING ADJACENT ABUTMENTS IN SAID PLANE AND OFFSET FROM SAID AXES, A TOGGLE SPRING INTERPOSED BETWEEN AND ENGAGING SAID ABUTMENTS TO EXERT A FORCE NORMALLY IN SAID PLANE AND URGING SAID ABOUTMENTS APART, SECOND MEANS ENGAGING SAID FIRST LEVER IN OFFSET RELATION WITH SAID FIRST AXIS AND EFFECTIVE TO PIVOT SAID FIRST LEVER IN ONE DIRECTION, BY AND IN RESPONSE TO A CHANGE IN PRESSURE, SPRING MEANS CONNECTED WITH SAID FIRST LEVER AND URGING THE SAME INTO PIVOTAL MOVEMENT IN THE OPPOSITE DIRECTION, AND CONTACT CLOSING MEANS RESPONSIVE TO PIVOTING OF SAID SECOND LEVER ABOUT SAID SECOND AXIS. 